CLAS physics database search results Measurement E151M485 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Data errors Systematic errors degrees 0.25 66 1.0483 0.5203 0.0708 0.45 282 1.0698 0.6018 0.072 0.65 270 -0.1413 0.533 0.0312 0.65 282 -0.3327 0.5038 0.0363 0.75 102 -0.369 0.4719 0.0375 0.75 258 -0.5702 0.4482 0.046 0.75 282 -0.5829 0.4381 0.0466 0.85 102 0.748 0.5577 0.0547 0.85 258 0.7682 0.5775 0.0557